Shipwrecks and Salvage > 5. Rates of Corrosion >
Compare and explain the solubility of selected gases at increasing depths in the oceans
- As ocean depth decreases, temperature falls and pressure increases.
- Thus, the solubility of gases is much greater at greater depths.
- However, when ocean water is very deep, there is not much mixing of surface water with bottom water, and concentrations are unlikely to reach equilibrium values.
- For oxygen and carbon dioxide, concentration is also affected by:
- Rates of photosynthesis, which is confined to where light can penetrate.
- Rates of respiration and decomposition, which increase with depth.
- Formation and dissolution of calcium carbonate by marine organisms and local acidic environments respectively.
- The net result for oxygen is that concentration decreases with depth, reaching a minimum at 500 to 800 metres, then increases lightly due to the inflow of cold, oxygen-rich currents.
- The net result for carbon dioxide is that concentration increases with depth.